445 MM 1957 Repair / Restoration

Hi,
I recently acquired a 1957, 445, Minneapolis Moline. It had been sitting for many years in the dirt outside. Here is my progress so far. After a soak in oil, I was able to get the engine to turn over and now running. It smokes pretty significantly. I replaced all the tires to get it rolling again. All the gears work as well as the Ampli-torque. I am waiting for axle seals to get enough oil in it completely diagnose the hydraulics. Here is the question. The engine is worn beyond specs in several area. [b:82115cc0e9]How do you decide how far to go in a rebuild?[/b:82115cc0e9]
A few more details: I replaced the water pump. I replaced the valve guides and reground all the valves and seats (easier attempt to reduce the oil burning) One valve was badly cracked. The oil burning was even worse, so I dug deeper. I found the compression rings have about a .09" end gap, and the oil rings have about a .18" end gap (worn out) Also, the main and rod bearings are worn partially into the copper lining. The crank end play is about .08" The decision is to decide how far to go to return it to light duty use for shows/parades. Any advise is much appreciated. Thank you.
 
I have Big Mo 500.When I got it it smoked so bad If you drove it into the barn the smoke was so bad you could not find the door to get back out. Slipped a ring back into cylinder and checked the end gap. The end gap was 3/8 of a inch. I honed cylinder and put in new rings and ground the valves, ground the crank and new bearing. If your not going to work it hard I'd just put in new bearing, rings, grind valves and enjoy.
 
Here are some photos

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When a head is redone on a weak or higher houred motor it will make little difference.
Should be rebuilt as one. One works against other. Have seen new head or heads on
cars/trucks. Motor won't last. 206 motors can be rebuilt quite reasonable. Way I check wear
on bottom end is use a screwdriver on flywheel timing hole. If moves any amount thrust on
rear main is gone. Rebuild time. Always change/check or update governor.
 
I may go against the grain on this, but you've done the 'top end'. If it was me, (And I have a 335 that I use for bushhogging,) I would put
it back in pretty good condition. As time goes on, things may change but right now you can get everything you need to put it back in good
condition.

I would re-grind the crank, and maybe get a machine shop or a mechanic familiar with engine rebuilds to help me decide whether the engine
can get by with a set of rings or not.

Your specs should read to at least one other decimal place. (.000). If you really have .090 end gap with your rings, the ring is shot and
probably the cylinder has too much taper too. Meaning just a set of rings may not help much.
 
The plan right now is to bore it .02 over. New pistons and rings. New main and rod bearings. The rod journals are in good condition however the mains are pretty rough. So I?ll take the block and crank to a machine shop and have it ground and fitted. I have a mill so I can bore the jugs out to size. The tractor was originally LP so it doesn?t have exhaust valve rotators. I might try to find some replacements at some point.
 
Here are a few more photos.
I am hoping the machine shop can weld up the thrust flange on the
crank and machine it back to size
 
Might be easier to find another crank. That is worn. Any crank up till 1962 will work,gas or diesel. All same on dimensions except later went to one piece rear seal rather than old bellows type.
 
I and a friend of my mine both work on MMs in the Phoenix area. Let?s us know if you might need
anything going forward.
 
(quoted from post at 16:31:08 03/03/19) I and a friend of my mine both work on MMs in the Phoenix area. Let?s us know if you might need
anything going forward.

Will you be at the AJ show March 9-10? I just joined the Arizona Early Days has Engine and Tractor Association. I will be showing a 1918 Fairbanks Z. (Tractor will definitely not be ready by then)
I would like to chat with you. I have lots of questions.
 
I am planning to be there with my 5 Star diesel and maybe one other tractor to be named. I look forward to meeting you.
 
if it is just for shows and parades and you don't want to sink a pile of money in it I would put in rings and brgs. you be surprised at how many years of use you will get . it don't need to be back to new spec's. also propane cause more engine wear than gas, and diesel causes less wear than both of those. get a new set of rings and put one in the top of cyl. at the wear point and check gap. an approx. new spec would be .016, and if you have say .025 with the new ring then I would just rering and rebrg. and call it good. same with the crank... get plastiguage and check the new brg to the crank and see what clearance you have.new clearance is about .001-.002 so if you have .003 -004 I would not be afraid to leave crank alone. lots of worn out engines running out there is worst shape. you can also use a straight 40 wt oil also which will help. that is my advice if you will only be running parades. its not like your in the field pulling a plow full throttle on a hard pull hr. after hr.
 
(quoted from post at 08:31:28 03/04/19) if it is just for shows and parades and you don't want to sink a pile of money in it I would put in rings and brgs. you be surprised at how many years of use you will get . it don't need to be back to new spec's. also propane cause more engine wear than gas, and diesel causes less wear than both of those. get a new set of rings and put one in the top of cyl. at the wear point and check gap. an approx. new spec would be .016, and if you have say .025 with the new ring then I would just rering and rebrg. and call it good. same with the crank... get plastiguage and check the new brg to the crank and see what clearance you have.new clearance is about .001-.002 so if you have .003 -004 I would not be afraid to leave crank alone. lots of worn out engines running out there is worst shape. you can also use a straight 40 wt oil also which will help. that is my advice if you will only be running parades. its not like your in the field pulling a plow full throttle on a hard pull hr. after hr.

Thank you for the advice! The main problem is the crank endplay is about .09-.1”. The thrust face on the crank is pretty worn. The current plan is to weld up the crank and regrind all the journals.
I have decided to bore it .02” over an put new pistons and rings also. I was hoping to keep this relatively inexpensive, but...
I bought the tractor for $150 so with new tires and all the engine work, I’ll be all in at 3k. In the end this is the right thing to do. It will be a good usable machine then. Thank you to everyone for your input and advice!
 
Hi,
We met at the AJ show. I gave you my card. Could you call me at your convenience.
I saw another crank at the machine shop that will need the same treatment mine did.
Curious if you know who's it is.
 
I'll call you. Did you get my text message back on the 13th? I sent a picture as well.

I'm not aware of anyone else working on a MM in the Phoenix area but it is good to know that there might be others getting repaired.
 

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